JPH10268300A - Reflective guest-host liquid crystal display - Google Patents

Abstract

[PROBLEMS] To improve display contrast while maintaining the pixel aperture ratio of a reflection type guest-host liquid crystal display device. SOLUTION: The reflection type guest-host liquid crystal display device includes a pair of substrates 1, 2 bonded to each other via a predetermined gap, and a guest-host liquid crystal 3 containing a dichroic dye and held in the gap. . At least the counter electrode 6 is formed on the upper substrate 1. On the lower substrate 2, a thin film transistor 8, a light reflection layer 9, a quarter-wave plate layer 10 formed thereon and provided with a contact hole communicating with the thin film transistor 8, and patterned and contacted thereon The pixel electrode 11 connected to the thin film transistor 8 through the hole is formed. A light-shielding black matrix BM is formed on the lower substrate 2 along boundaries of the individual pixel electrodes 11. The light reflection layer 9 is formed of a resin film 9a having irregularities and having a light-shielding property, and a reflective metal film 9b formed on the surface thereof in a shape matching the pixel electrode 11.
Consists of The black matrix BM is formed using a part of the resin film 9a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a reflection type guest-host liquid crystal display device. More specifically, the present invention relates to a technology for improving the efficiency of using incident light by incorporating a quarter-wave plate layer and a light reflection layer in a device. More specifically, the present invention relates to a structure of a black matrix for shielding the periphery of a pixel from light.

[0002]

2. Description of the Related Art A reflection type guest-host liquid crystal display device having a built-in quarter-wave plate layer and a light reflection layer is disclosed, for example, in Japanese Patent Laid-Open No.
FIG. 6 shows a cross-sectional structure thereof. This reflective liquid crystal display device 101 includes a pair of upper and lower substrates 102 and 103, a guest host liquid crystal 104,
Dichroic dye 105, pair of upper and lower transparent electrodes 106 and 11
0, a pair of upper and lower alignment layers 107 and 111, and a light reflection layer 10
It is configured to include the eighth and quarter wave plate layers 109.
The pair of substrates 102 and 103 are made of, for example, glass, quartz,
It is made of an insulating material such as plastic. Further, at least the upper substrate 102 is transparent.
A dichroic dye 10 is provided between the pair of substrates 102 and 103.
5 is held. The guest host liquid crystal 104 is a nematic liquid crystal molecule 104a.
And the dichroic dye 105 is a so-called p-type dye having a transition dipole moment almost parallel to the long axis of the molecule. Although not shown, a switching element is integrally formed on the inner surface 102a of the upper substrate 102. Also,
The transparent electrode 106 is patterned as a pixel electrode in a matrix and is driven by a corresponding switching element. Further, the inner surface of the upper substrate 102 is covered with an alignment layer 107 made of polyimide resin or the like. The surface of the alignment layer 107 is, for example, subjected to a rubbing treatment, so that the nematic liquid crystal molecules 104a are horizontally aligned.

On the other hand, the inner surface 103a of the lower substrate 103
A light reflection layer 108 made of aluminum or the like and a quarter-wave plate layer 109 made of a polymer liquid crystal or the like are formed in this order. Further, a transparent electrode 110 and an alignment layer 111 are formed on the quarter-wave plate layer 109 in this order.

Next, the operation of the reflective guest-host liquid crystal display device 101 for monochrome display will be briefly described. In the state where no voltage is applied, the nematic liquid crystal molecules 104a are horizontally aligned and the dichroic dye 1
05 is similarly oriented. When the light incident from the upper substrate 102 side travels to the guest-host liquid crystal 104, a component of the incident light having a vibration plane parallel to the major axis direction of the molecules of the dichroic dye 105 is caused by the dichroic dye 105. Absorbed.
In addition, a component of the dichroic dye 105 having a vibration plane perpendicular to the major axis direction of the molecule passes through the guest-host liquid crystal 104 and forms a quarter-wavelength formed on the inner surface 103 a of the lower substrate 103. The light reflected by the light reflecting layer 10
Reflect at 8. At this time, the polarization of the reflected light is reversed,
The dichroic dye 10 passes through the quarter-wave plate layer 109 again.
5 has a vibration surface parallel to the long axis direction of the molecule. Since this component is absorbed by the dichroic dye 105, almost complete black display is obtained.

On the other hand, when a voltage is applied, the nematic liquid crystal molecules 104a are vertically oriented along the direction of the electric field, and the dichroic dye 105 is similarly oriented. Light incident from the upper substrate 102 side passes through the guest-host liquid crystal 104 without being absorbed by the dichroic dye 105, and further passes through the quarter-wave plate layer 1.
At 09, the light is reflected by the light reflection layer 108 without being substantially affected. The reflected light passes through the quarter-wave plate layer 109 again and exits without being absorbed by the guest-host liquid crystal 104.
Therefore, white display is obtained.

In the conventional structure shown in FIG. 6, a switching element for driving a pixel is formed on an incident side substrate. Since the switching element is formed of a thin film transistor or the like and blocks incident light, the aperture ratio of the pixel is reduced accordingly. To cope with this, a structure in which switching elements are integratedly formed on a substrate on the reflection side has been developed, and an example thereof is shown in FIG. As shown in the drawing, the upper substrate 201 has a counter electrode 203a made of a transparent electrode formed over the entire surface, and the lower substrate 2
Numeral 02 has a pixel electrode 204a composed of a reflective electrode subdivided in a matrix. That is, this example is an active matrix type. On the inner surface of the substrate 202, in addition to the pixel electrodes 204a patterned in a matrix, thin-film transistors TFT are integrally formed correspondingly. This TFT becomes a switching element for individually driving the pixel electrode 204a. That is, the TFT is selectively turned on / off to write a signal voltage to the corresponding pixel electrode 204a. The drain region D of the TFT is a pixel electrode 204
a, and the source region S is connected to the signal wiring 221. The gate electrode G of the TFT is connected to a gate wiring. Further, an auxiliary capacitance Cs is also formed corresponding to each pixel electrode 204a. The pixel electrode 204a is electrically separated from the TFT, the storage capacitor Cs, the signal wiring 221 and the like by the flattening layer 222. On the other hand, a counter electrode 203a is formed entirely on the inner surface of the upper substrate 201.
Both substrates 20 opposed to each other with a predetermined gap therebetween
An electro-optical body 205 is held between the first and second lenses 202. This electro-optical body 205 has a laminated structure including a guest-host liquid crystal 206 and a quarter-wave plate layer 207. The guest host liquid crystal 206 contains a nematic liquid crystal molecule 209 and a dichroic dye 208, and is horizontally aligned by upper and lower alignment layers 210 and 211. The quarter-wave plate layer 207 is formed along the pixel electrode 204a.

When a signal voltage is written to the pixel electrode 204a, an electric field is generated between the pixel electrode 204a and the facing opposing electrode 203a.
The guest host liquid crystal 206 changes between an absorption state and a transmission state. Since this optical change appears for each pixel electrode, a desired image display can be performed. Pixel electrode 204a
, A TFT, an auxiliary capacitor Cs, a signal wiring 221, and the like are arranged below the pixel. Since these components do not intervene in the incident optical path, they do not affect the pixel aperture ratio. In other words, the area of the pixel electrode 204a can be used as it is as a pixel opening, and a bright display can be achieved.

[0008]

The above-mentioned reflection type guest-host liquid crystal display device performs display using external light such as natural light without using a backlight for back illumination, so that a bright screen is required. It is necessary to increase the aperture ratio of the pixel. In this regard, as described above, the structure shown in FIG. 7 can sufficiently secure the aperture ratio. On the other hand, when performing color display, a color filter colored in three primary colors corresponding to each pixel is provided on the counter substrate 201 side. In order to improve the contrast in color display, it is necessary to provide a black light shield (black matrix) along the boundaries between individual pixels. Conventionally, a black matrix has been provided on a counter substrate similarly to a color filter. However, in this structure, the opposing substrate 20 on which the black matrix is formed is formed.
It is necessary to perform accurate positioning between the substrate 1 and the substrate 202 on which the TFT is formed. However, there is a limit in mechanical accuracy, and a certain amount of error occurs in alignment. In order to absorb this error, the width of the black matrix is designed to be wide to some extent, and there is a problem that the aperture ratio of the pixels is sacrificed accordingly.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems of the prior art, the following measures have been taken. That is, the reflective guest-host liquid crystal display device according to the present invention has, as a basic configuration, a pair of substrates bonded to each other with a predetermined gap therebetween,
A guest-host liquid crystal containing a dichroic dye and held in the gap. At least one counter electrode is formed on one substrate. On the other substrate, a switching element, a light reflection layer, a quarter-wave plate layer formed above these layers and provided with a contact hole communicating with the switching element, and a quarter-wave plate layer And a pixel electrode which is patterned and connected to the switching element via the contact hole. As a characteristic feature, a light-shielding black matrix is formed on the other substrate along boundaries of individual pixel electrodes. Specifically, the light reflection layer is formed of a resin film having irregularities and having a light-shielding property, and a reflective metal film formed on the surface thereof in a shape matching the pixel electrode. Is formed utilizing a part of the resin film. Preferably, the resin film is a photosensitive resin film to which a black pigment or dye is added. Also preferably, a flattening layer for filling irregularities is interposed between the light reflecting layer and the quarter-wave plate layer, and the flattening layer is colored corresponding to each pixel electrode. Functions as a color filter.

According to the present invention, the black matrix and the color filters are provided not on the substrate on which the opposing electrodes are formed, but on the substrate on which the pixel electrodes and switching elements are formed. It has a so-called on-chip structure, the black matrix and the color filter can be aligned with the pixel electrode with high accuracy, and a sufficient pixel aperture ratio can be secured. Unlike the related art, there is no need to consider the overlay accuracy of the substrate on which the counter electrode is formed and the substrate on which the pixel electrode is formed. Accordingly, there is no need to provide a margin for absorbing errors in a pattern such as a black matrix.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a basic configuration of a reflective guest-host liquid crystal display device according to the present invention,
(A) is a sectional view of one pixel, and (B) is a plan view of one pixel. As shown in the figure, this display device is configured using a pair of upper and lower substrates 1 and 2 joined to each other with a predetermined gap therebetween. The upper substrate 1 is located on the incident side and is made of a transparent base material such as glass. On the other hand, the lower substrate 2 is located on the reflection side, and it is not always necessary to use a transparent material. A guest host liquid crystal 3 is held in a gap between the pair of substrates 1 and 2. The guest-host liquid crystal 3 mainly includes, for example, nematic liquid crystal molecules having negative dielectric anisotropy, and contains a dichroic dye at a predetermined ratio. A counter electrode 6 and an alignment layer (not shown) are formed on the inner surface of the upper substrate 1. The counter electrode 6 is made of a transparent conductive film such as ITO. The alignment layer is made of, for example, a polyimide film, and vertically aligns the guest-host liquid crystal 3. The present invention is not limited to this, and the guest-host liquid crystal may be horizontally aligned as shown in FIGS. In the present embodiment, the guest host liquid crystal 3 is vertically aligned when no voltage is applied, and shifts to horizontal alignment when a voltage is applied.

On the lower substrate 2, at least a switching element comprising a thin film transistor 8, a light reflection layer 9, a quarter-wave plate layer 10, and a pixel electrode 11 are formed.
The quarter wavelength plate layer 10 is formed above the thin film transistor 8 and the light reflection layer 9, and has a contact hole communicating with the thin film transistor 8. The pixel electrode 11 is patterned on the quarter-wave plate layer 10. Therefore, it is possible to apply a sufficient electric field to the guest host liquid crystal 3 between the pixel electrode 11 and the counter electrode 6. The pixel electrode 11 is electrically connected to the thin film transistor 8 via a contact hole opened in the quarter-wave plate layer 10.

As a characteristic feature, a light-shielding black matrix BM is formed on the lower substrate 2 along boundaries of the individual pixel electrodes 11. On the other hand, the light reflection layer 9 is a resin film 9
a and a metal film 9b. The resin film 9a has irregularities and has a light shielding property. The metal film 9b is formed on the resin film 9a in a shape matching the pixel electrode 11. In the present embodiment, the above-described black matrix B
M is formed using a part of the resin film 9a having a light shielding property. The resin film 9a is, for example, a photosensitive resin film to which a black pigment or dye is added. It should be noted that a flattening layer 14 for filling irregularities is interposed between the light reflecting layer 9 and the quarter-wave plate layer 10. The flattening layer 14 is formed on each pixel electrode 11
And functions as a color filter. As described above, the present invention employs a so-called on-chip structure in which a black matrix BM and a color filter are integrated on the lower substrate 2 side on which the pixel electrodes 11 and the thin film transistors 8 are formed.

In the present invention, the uneven resin film 9a constituting the light-reflective layer 9 having a scattering property is made black to provide a light-shielding property. By using a part of the black resin film 9a for the black matrix BM, an on-chip structure of the black matrix is realized. A reflective metal film 9b made of aluminum or the like is formed on the surface of the black resin film 9a. This metal film 9b is formed on the pixel electrode 11 located on the upper layer.
And the same pattern. Therefore, the pixel electrode 11
In the opening defined by, the black resin film 9a is completely covered with the metal film 9b and cannot be visually recognized from the outside. In other words, only the metal film 9b with the unevenness is observed in the opening. As shown in FIG. 1A, a part of the black resin film 9a also extends between the pixel electrodes 11. The metal film 9b is not formed in this portion. Therefore, the black resin film 9a has a structure in which the black resin film 9a can be visually recognized between the adjacent pixel electrodes 11, and this becomes the black matrix BM as shown in FIG. That is, the black matrix BM is formed in a lattice shape so as to surround the pixel electrode 11. The width of the black matrix BM is the metal film 9b.
And it can be controlled accurately.
In other words, the pattern accuracy of the black matrix BM is determined by the pattern accuracy of the metal film 9b, and the black resin film 9a
Does not depend at all on the pattern accuracy of As described above, in the present invention, the aperture ratio of the pixel is substantially determined by the pattern accuracy of the metal film 9b. As shown in (B), a gate wiring 16x and a signal wiring 21y are formed below a black matrix BM formed in a lattice shape. The resin film 9a is made of a photosensitive resin film such as a photoresist, and has a black color. The photoresist may be either a negative type or a positive type. To make the photoresist black, for example, a black dye or pigment is added to the photoresist material in advance. Alternatively, after a transparent photoresist is patterned into a predetermined shape, the photoresist may be dyed black with a dye or the like. In some cases, after a transparent photoresist is patterned into a predetermined shape, heat treatment may be applied to make the photoresist black. The flattening layer 14 is colored corresponding to each pixel electrode 11, and functions as an RGB or YMC color filter. Since the color filter also has an on-chip structure, the aperture ratio of the pixel does not decrease. The color filter can be formed by a dyeing method. Alternatively, a printing method may be employed.
Further, it can be formed using a photoresist in which a pigment or a dye is dispersed. By forming the black matrix and the color filter on the lower substrate on-chip, it is only necessary to form the counter electrode 6 on the upper substrate 1, and the accuracy of superposition of the pair of upper and lower substrates 1 and 2 is improved. There is no need to consider.

With continued reference to FIG. 1, a specific description will be given for each element. In the present embodiment, the quarter-wave plate layer 10 is composed of a uniaxially oriented polymer liquid crystal film. In general, a base alignment layer (not shown) is used to uniaxially align the polymer liquid crystal film. A flattening layer 14 is interposed to fill the unevenness of the thin film transistor 8 and the light reflecting layer 9, and the above-described underlying alignment layer is formed on the flattening layer 14. Then, the quarter-wave plate layer 10 is also formed on the surface of the flattening layer 14. In this case, the pixel electrode 11 is connected to the thin film transistor 8 via the contact hole provided in the quarter-wave plate layer 10 and the flattening layer 14 and the intermediate electrode 12a. The light reflection layer 9 is subdivided corresponding to each pixel electrode 11. Each of the subdivided portions is connected to the same potential as the corresponding pixel electrode 11. With such a configuration, the light reflection layer 9 and the pixel electrode 1
Quarter wave plate layer 10 or flattening layer 1
No unnecessary electric field is applied to 4. The light reflecting layer 9 is provided with a scattering reflecting surface as shown in the figure to prevent the specular reflection of the incident light and improve the image quality. The thin film transistor 8 has a bottom gate structure, and has a stacked structure in which a gate electrode 16, two layers of gate insulating films 17a and 17b, and a semiconductor thin film 18 are stacked in order from the bottom. The semiconductor thin film 18 is made of, for example, polycrystalline silicon.
The channel region which is aligned with is protected by a stopper 19 from above. In the present embodiment, the thin film transistor 8 has a double gate structure using two gate electrodes 16, but may have a single gate structure instead. The bottom gate type thin film transistor 8 having such a configuration is covered with two interlayer insulating films 20a and 20b. A pair of contact holes are opened in the interlayer insulating films 20a and 20b, and a source electrode 21 and a drain electrode 22 are electrically connected to the thin film transistor 8 through these. The source electrode 21 forms a part of the signal wiring 21y described above. The drain electrode 22 has the same potential as the light reflection layer 9. The pixel electrode 11 is electrically connected to the drain electrode 22 via the intermediate electrode 12a and the light reflection layer 9. On the other hand, a signal voltage is supplied to the source electrode 21 via the signal wiring 21y. In this embodiment, the auxiliary capacitor C has the same layer structure as the thin film transistor 8.
s is also formed.

Next, a method for manufacturing the reflection type guest-host liquid crystal display device according to the present invention will be specifically described with reference to the process charts of FIGS. Here, for ease of understanding, the manufacturing method will be described here in a more simplified form of the structure shown in FIG. First, as shown in a step (A1) of FIG. 2, a thin film transistor 8 is integratedly formed on the surface of the insulating substrate 2.
Specifically, a refractory metal film is formed on the surface of the substrate 2 and then patterned into a predetermined shape to process the gate electrode 16. Silicon oxide or silicon nitride is deposited by CVD or the like so as to cover the gate electrode 16, and a gate insulating film 17 is formed.
And Further, a semiconductor thin film 18 made of polycrystalline silicon or the like is formed thereon by CVD or the like. This semiconductor thin film 1
8 is patterned in an island shape according to the shape of the element region of the thin film transistor 8. A stopper 19 made of silicon oxide or the like on the semiconductor thin film 18 in alignment with the gate electrode 16.
Is formed by patterning. Using the stopper 19 as a mask, impurities are implanted into the semiconductor thin film 18 by ion doping or ion implantation. Thus, a thin film transistor 8 having a bottom gate structure is obtained. Note that the present invention is not limited to this, and a thin film transistor having a top gate structure may be used instead of a thin film transistor having a bottom gate structure as a switching element. Alternatively, a two-terminal element such as a MIM may be used instead of a thin film transistor (TFT). PGS or the like is deposited so as to cover the thin film transistor 8 to form an interlayer insulating film 20. After opening a contact hole in the interlayer insulating film 20, aluminum or the like is entirely formed. This is patterned into a predetermined shape and processed into the source electrode 21 and the signal wiring. As shown, the source electrode 21 is electrically connected to the source region of the thin film transistor 8 via a contact hole.

In step (A2), a photosensitive resin film 9a is applied to the entire surface of the interlayer insulating film 20. As the photosensitive resin film 19a, for example, a photoresist can be used. A black pigment or dye is added to this photoresist in advance, so that light-shielding properties are imparted. In step (A3), the photoresist is exposed through a predetermined mask, and the resin film 9a is patterned into, for example, a discrete columnar shape. At this time, the resin film 9a is also left in a portion functioning as the black matrix BM. Proceeding to the step (A4), the insulating substrate 2 is subjected to a heat treatment to reflow the resin film 9a. By this reflow, the cylindrical shape of the photoresist is gently deformed, and a desired uneven shape is obtained.

Proceeding to step (B) in FIG. 3, a metal film 9b of aluminum or the like having a desired film thickness and good reflectance is formed on the uneven surface of the resin film 9a by vacuum evaporation or the like. By setting the depth dimension of the unevenness to several μm, good light scattering characteristics can be obtained, and the metal film 9b exhibits white. The metal film 9b is patterned into a predetermined shape, and the light reflection layer 9 matched with the pixel electrode is obtained. At this time, at the same time, the metal film 9b is removed from above the signal wiring including the source electrode 21, and the black matrix BM is formed. Further, the drain electrode 22 of the thin film transistor 8 is formed simultaneously with the metal film 9b. As is apparent from the figure, the metal film 9b is formed on the drain electrode 2
2 and the same potential.

Proceeding to the step (C), a flattening layer 14 is formed on the light reflecting layer 9 to fill the irregularities. In the present embodiment, a photoresist colored in RGB is used for the planarization layer 14. First, a photoresist colored R (red) is applied by spin coating to fill in irregularities. This is matched with the light reflection layer 9 and patterned to form a red color filter. Similar processing is repeated using G (green) and B (blue) photoresists to provide RGB color filters. Thereafter, the process proceeds to the formation of a quarter-wave plate layer. First, the base alignment layer 13 is formed on the flattening layer 14, and then a polymer liquid crystal is applied thereon and is uniaxially aligned to form a quarter-wave plate layer. At this time, the interposition of the planarizing layer 14 enables stable formation of the base alignment layer 13 and rubbing. The base alignment layer 13 is made of, for example, a polyimide film, and is subjected to rubbing along a predetermined alignment direction. In some cases, the planarization layer 14
May be directly rubbed.

Next, the process proceeds to step (D), and the quarter-wave plate layer 10 is actually formed on the under orientation layer 13 described above.
Specifically, the polymer liquid crystal is coated with a predetermined thickness to form the base alignment layer 13.
Apply on top. This polymer liquid crystal is a material capable of phase transition between a high temperature side nematic liquid crystal phase and a low temperature side glass solid phase at a predetermined dislocation point. For example, this polymer liquid crystal is in a glassy state at room temperature, and is preferably 100 ° C.
As described above, it is a main chain type or a side chain type having a dislocation point. This polymer liquid crystal is a transparent substance that does not optically absorb in the visible region. This polymer liquid crystal is dissolved in an organic solvent (for example, a mixed solution of cyclohexane and n-butanone), and then applied to the surface of the base alignment layer 13 by spin coating.
When spin coating is performed, conditions such as the concentration of the solution and the number of spin rotations are appropriately set so that the thickness of the formed thin film causes a phase difference of λ / 4 in the visible light region. Here, λ is the wavelength of the incident light. Thereafter, a temperature treatment is performed to heat the substrate 2 once to a temperature equal to or higher than the dislocation point, and then to cool the substrate 2 to a room temperature equal to or lower than the dislocation point. To form For example, heating and cooling are performed on a polymer liquid crystal material having a dislocation point of 100 ° C. or higher and liquid crystal molecules introduced into the main chain or side chain of the polymer. In the film formation stage, the liquid crystal molecules contained in the polymer liquid crystal are in a random state, but after cooling, the liquid crystal molecules are aligned along the alignment direction, and a desired uniaxial optical anisotropy can be obtained. Specifically, the substrate 2 on which the polymer liquid crystal has been formed is put into an oven set to a nematic phase temperature or an isotropic phase temperature in advance and heated. Then, it is cooled down and returned to room temperature. The base alignment layer 1 in which the polymer liquid crystal coated in this way has been subjected to an alignment treatment in advance.
3 are aligned.

Next, as shown in FIG.
A contact hole communicating with the drain electrode 22 of the thin film transistor 8 below the stack of the base alignment layer 13 and the planarization layer 14 is opened. First, in step (E), a photosensitive film 10a is applied to the entire surface of the quarter-wave plate layer 10. Proceeding to step (F), exposure processing of the photosensitive film 10a is performed. For example, by exposing the photosensitive film 10a through the mask 10b, a portion irradiated with light is cured, while a portion not irradiated with light is left uncured.
In this embodiment, a water-soluble photosensitive film 10a is used. Proceeding to step (G), a development process is performed using pure water or the like,
An uncured portion is removed from the photosensitive film 10a. By such a photolithography process, the photosensitive film 10a is patterned into a desired shape. That is, a window 10c is opened in the photosensitive film 10a so as to be aligned with the drain electrode 22 as shown. In step (H), the quarter-wave plate layer 10, the underlying alignment layer 13, and the planarizing layer 14 are etched using the patterned photosensitive film as a mask to form contact holes. This etching step can employ a dry etching method.

Proceeding to the step (I) of FIG. 5, the pixel electrode 1 is connected to the drain electrode 22 of the thin film transistor 8 via the contact hole 12 on the quarter-wave plate layer 10.
Form one. For example, the pixel electrode 11 can be formed by forming a transparent conductive film made of ITO or the like by sputtering and then patterning it into a predetermined shape by etching. As is clear from the figure, the pixel electrodes 11 adjacent to each other
Is aligned with the underlying black matrix BM. Proceeding to the step (J), the alignment layer 15 is formed so as to cover the pixel electrode 11. For example, a desired alignment layer 15 can be obtained by forming a polyimide film for vertical alignment.
Finally, in a step (K), the transparent substrate 1 on which the counter electrode 6 and the alignment layer 7 are formed in advance is bonded to the insulating substrate 2 via a predetermined gap. When the guest host liquid crystal 3 is injected into the gap between the two substrates 1 and 2, the reflection type guest host liquid crystal display device is completed. The guest-host liquid crystal 3 is obtained by adding a dichroic dye 5 serving as a guest to a nematic liquid crystal 4 serving as a host.

[0023]

As described above, according to the present invention,
In a reflective guest-host liquid crystal display device in which a quarter-wave plate layer, a light reflection layer, a pixel electrode, a thin film transistor, and the like are integrated on an insulating substrate, an aperture ratio is formed by forming a black matrix between pixels on the insulating substrate. It has become possible to improve the contrast without reducing.
In particular, by using a photoresist in which a black pigment or a dye is added to an uneven resin film serving as a base of a light reflection layer, a black matrix can be formed between pixels without reducing the aperture ratio and increasing the number of steps. And display contrast can be significantly improved. Furthermore, by forming a color filter on an insulating substrate using not only a black matrix but also a flattening layer, only the counter electrode needs to be formed on the counter substrate, and the overlay accuracy of both substrates is considered. The pixel aperture ratio can be improved accordingly.

[Brief description of the drawings]

FIG. 1 is a sectional view and a plan view showing a basic configuration of a reflection type guest-host liquid crystal display device according to the present invention.

FIG. 2 is a process diagram showing a method for manufacturing a reflective guest-host liquid crystal display device according to the present invention.

FIG. 3 is a process diagram illustrating a method for manufacturing a reflective guest-host liquid crystal display device according to the present invention.

FIG. 4 is a process diagram showing a method for manufacturing a reflective guest-host liquid crystal display device according to the present invention.

FIG. 5 is a process diagram showing a method for manufacturing a reflective guest-host liquid crystal display device according to the present invention.

FIG. 6 is a cross-sectional view illustrating an example of a conventional reflective guest-host liquid crystal display device.

FIG. 7 is a cross-sectional view illustrating another example of a conventional reflective guest-host liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Substrate, 2 ... Substrate, 3 ... Guest-host liquid crystal, 6 ... Counter electrode, 8 ... Thin-film transistor, 9
... light reflection layer, 9a ... resin film, 9b ... metal film, 10 ... quarter-wave plate layer, 11 ... pixel electrode, 14 ... flattening layer, BM ..Black matrix

Claims (4)

[Claims] 1. A semiconductor device comprising: a pair of substrates joined to each other via a predetermined gap; and a guest-host liquid crystal containing a dichroic dye and held in the gap. At least one counter electrode is formed on one of the substrates. The other substrate has a switching element, a light reflecting layer, a quarter-wave plate layer formed thereon and provided with a contact hole communicating with the switching element, and A reflective guest-host liquid crystal display device in which a pixel electrode patterned on a wavelength plate layer and connected to the switching element through the contact hole is formed, and the other substrate is provided with individual pixel electrodes. A reflective guest-host liquid crystal display device, wherein a light-shielding black matrix is formed along a boundary. 2. The light reflection layer comprises a resin film having irregularities and a light-shielding property, and a reflective metal film formed on a surface thereof in a shape matching a pixel electrode. 2. The reflection-type guest-host liquid crystal display device according to claim 1, wherein the reflection-type guest-host liquid crystal display device is formed using a part of the resin film. 3. The reflection-type guest-host liquid crystal display device according to claim 2, wherein the resin film is a photosensitive resin film to which a black pigment or dye is added. 4. A flattening layer for filling unevenness is interposed between the light reflecting layer and the quarter-wave plate layer, and the flattening layer is colored corresponding to each pixel electrode. 3. The reflective guest-host liquid crystal display device according to claim 2, wherein the reflective guest-host liquid crystal display device functions as a cage color filter.